1. Field of the Invention
This invention relates, in general, to prostheses which are externally attachable to severed or amputated limbs and, more specifically, to apparatus for use in attaching prostheses to the limbs.
2. Description of the Prior Art
It is common to attach a prosthesis or artificial limb externally onto the stump of a limb of an individual which has been amputated or otherwise severed in order to provide a measure of use of the limb to the individual. Specifically, a strap and harness assembly is utilized which engages the stump of the limb. During use of the weight bearing limb, such as a leg or arm, forces are generated which are transmitted through the prosthesis directly to the flesh surrounding the stump. Since it is difficult to insure a secure, non-slip engagement between the prosthesis and the limb, the forces generated during use of the prosthesis create movement of the prosthesis relative to the stump which result in irritation of the flesh surrounding the stump and discomfort to the wearer which makes it difficult, if not impossible, to effectively use the prosthesis in a normal manner.
One solution to the above-listed patents is shown in my U.S. Pat. No. 4,547,912. This patent proposes employing an amputation apparatus comprising two parts. The first part is a cap having an internal cavity for insertion over the bone and an opposed outwardly extending boss. The second part comprises a plate having an internal cavity mountable over the outwardly extending boss of the cap. The plate has a radial extent substantially greater than the radial extent of the cap to define an equal weight distribution surface for internal and external forces over the entire bottom surface of the stump.
While the two piece amputation apparatus constitutes an improvement over the prior art, certain problems may still occur. The bone cap disclosed in U.S. Pat. No. 4,547,912 is comprised of an open top, a bottom and side walls. Because the bottom surface is continuous, the bone end of the an amputated limb over which such a cap is placed is isolated from the tissue of the amputated limb which is wrapped around the plate part of the two-piece assembly. Since the bone within the amputated limb continues to be a living tissue, it would be less likely to suffer deterioration and subsequent withering if it were allowed to be in contact with muscle and skin tissue contained in the amputated limb. Additionally, the problem of slippage between an amputated limb and the prosthesis remains unresolved, since no provision in U.S. Pat. No. 4,547,912 is made for a secure, non-slip attachment.
Thus, it would be desirable to provide an amputation apparatus which overcomes the problems described above for use with a prosthesis attached externally to a severed or amputated limb. It would also be desirable to provide an amputation apparatus which allows the bone end to remain in contact with the other tissue contained in the amputated limb. Finally, it would be desirable to provide an amputation apparatus which may be attached to an external prosthesis in a secure, non-slip manner.